This invention relates to shaving systems.
In shaving systems of the wet shave type, factors such as the frictional drag of the razor across the skin, the force needed to sever hairs, and irritation of preexisting skin damage can create a degree of shaving discomfort. Discomfort and other problems accompanying wet shaving systems can be alleviated by the application of shaving aids to the skin. Shaving aids may be applied prior to, during, or after shaving.
A number of problems accompany the use of pre- and post-applied shaving aids. Pre-applied shaving aids can evaporate or can be carried away from the site of application by repeated strokes of the razor. Post-applied shaving aids are not present on the skin during shaving and thus their application may be too late to prevent an unwanted effect. Moreover, the application of both pre-applied and post-applied shaving aids add additional steps to the shaving process.
It is known to incorporate a shaving aid into a razor by mounting a composite including the shaving aid to the razor. For example, Rogers et al., U.S. Pat. No. 5,113,585 describes a composite including a water-insoluble matrix material, a water-soluble shaving aid, and a low molecular weight release enhancing agent. When exposed to water during shaving, the water-soluble shaving aid leaches from the composition onto the skin. The release enhancing agent also dissolves in the water and improves the release of the water-soluble shaving aid from the composite.
The invention features a wet shaving system. The system includes a blade member including one or more blades and an external skin-engaging portion in proximity to the blade member. The shaving system may be, for example, a disposable shaving cartridge adapted for coupling to or uncoupling from a razor handle, or a shaving head which is integral with a razor handle so that the complete razor is discarded as a unit when the blade or blades become dulled. The blade edge cooperates with the skin engaging portion to define shaving geometry.
Significantly, the skin-engaging portion includes a polymeric shaving aid composite including two adjacent exposed lengthwise-extending portions, each containing a shaving aid. The shaving aid included in each portion may be the same or different. The composite can be, for example, an extruded composite.
A shaving aid composite having adjacent, lengthwise-extending portions provides a number of potential design advantages. For example, one portion may contain a larger quantity of water-insoluble resin than the second portion, while the second portion contains a larger quantity of shaving aid than the first portion. The first portion, then, may provide support to the second portion, which in turn may release a significant quantity of shaving aid during shaving without breaking down or causing the shaving geometry to change significantly.
Furthermore, the arrangement provides a way to incorporate incompatible shaving aids into the same shaving system. One shaving aid, for example, may chemically react with another, if they are mixed together. Likewise, a shaving aid, if included in too large a quantity in a composite that also includes another shaving aid, may unfavorably impact the wear characteristics of the composite or, for example, when the other shaving aid is a lubricous water-soluble polymer, to reduce the lubricity provided by the composite. Similarly, one shaving aid may require elevated processing temperatures during an extrusion procedure that would cause a second shaving aid to decompose. By including these shaving aids in different portions of the composite, the composite can be coextruded with different processing temperatures for each portion.
Moreover, the two portions can provide a desirable surface geometry for the composite. For example, the portions may be rounded, which may provide an enhanced skin-engaging surface on the composite. Alternatively, the exposed surface of one portion may be raised slightly relative to the second portion, which may enhance the wear characteristics of the first portion.
The invention also features a shaving system that includes two adjacent exposed lengthwise extending portions, one of which contains a colorant. The second portion has a different color than the first portion; it may, for example, contain no colorant or a colorant different from the colorant used in the first portion. The colorant in the first portion is released (e.g., by leaching or by wear) during shaving. When first used, the composite preferably has a striped appearance caused by the contrast between the two positions. One or both of the portions may also contain a shaving aid.
Other features and advantages of the invention will be apparent from the description of the preferred embodiment thereof, and from the claims.